Uefa delegates will measure the temperature with a wet bulb globe temperature (WBGT) thermometer at the end of the teams’ warm-ups.
Different from a normal thermometer, the WBGT thermometer accounts for temperature, humidity, wind speed, sun angle and cloud cover to determine the heat.
If the WBGT temperature exceeds 32C, cooling breaks – which can last between 90 seconds and three minutes – will be introduced for players during the match.
If the temperature is below those thresholds, the implementation of drinks breaks is at the discretion of the referee.
A heat warning has been issued by Uefa for all matches on Wednesday, Thursday and Friday, with fans allowed to bring a water bottle up to half a litre in size into the stadium on those days.
Uefa has also encouraged fans to re-fill their bottles and cups in the stadium bathrooms, and to seek shade in the fan zones across the country.
